Scouring the Business of Technology

How the Linux kernel works

The kernel is a piece of software that, roughly speaking, provides a layer between the hardware and the application programs running on a computer. In a strict, computer-science sense, the term ‘Linux’ refers only to the kernel – the bit that Linus Torvalds wrote in the early 90s.

All the other pieces you find in a Linux distribution – the Bash shell, the KDE window manager, web browsers, the X server, Tux Racer and everything else – are just applications that happen to run on Linux and are emphatically not part of the operating system itself. To give some sense of scale, a fresh installation of RHEL5 occupies about 2.5GB of disk space (depending, obviously, on what you choose to include). Of this, the kernel, including all of its modules, occupies 47MB, or about 2%…